Combustion spray nozzle



Sept. 4, 1951 E. o. oLsoN COMBUSTION SPRAY NOZZLE Filed Aug. 20, 1947Patented Sept. 4, 1951 COMBUSTION SPRAY N OZZLE Eugene 0. Olson, DesMoines, Iowa, assigner to Delavan Manufacturing Company, Des Moines,Iowa, a corporation of Iowa Application August 20, 1947, serial No.769,661

4 Claims.

The present application relates to combustion spray nozzles of the typeused for combustion engines, and particularly to an improvement foreffecting more eflicient operation of the nozzles.

The general type of nozzle to which the present invention is applied isone in which fuel is supplied to the nozzle under pressure and only aportion thereof enters the combustion space desired, the remaining beingwithdrawn through a by-pass channel and returned to the source of fuelsupply. The purpose of such an arrangement is to accomplish flow of fuelinto the combustion space with some independence from the feed linepressure in order. that the flow-pressure characteristic can be made toconform to a straight line graph or otherwise varied as desired. Withoutthe provision of such by-pass feature, the iiow of fuel into thecombustion space is approximately proportional to the. square root ofthe pressure applied.

For the purposes of explaining the effectiveness of the presentinvention a brief statement of the operation of such nozzles is heregiven. Fuel is supplied under pressure to a swirl chamber throughtangential passages. The fuel entering the swirl chamber swirls aroundthe periphery thereof and passes into the combustion chamber through anozzle orice which is disposed axially of the swirl chamber. The by-passchannel leads from the swirl chamber axially thereof and from a positionopposite the nozzle orifice. A hollow vortex forms in the swirl chamberand, by withdrawing fuel from the swirl chamber through the ley-passchannel,Y in instances where the present invention has not been applied,air from the hollow vortex is withdrawn with the by-passed fuel, andinterferes with proper operation of the fuel nozzle when the bypassedfuel is returned to thesource. of supply.

An object of the present invention is, therefore, the provision of meansto. prevent thewithdrawal of air from the swirl chamber through theby-pass channel.

Another. object is the provision of such means whichcan be inserted in astandard nozzlei without the necessity of re-designing the nozzle.

Stillanother object is the'provision of such a means which is simpleandeconomical inimanufacture as well as being easily placed in the nozzle.

With these and other objects. in View, myinvention consists in theconstruction, arrange'- ment, and combination of the various partsofmydevice whereby the objects contemplated are attained, las hereinaftermore fully setiforth; pointed out in my claims, and illustratedini theaccom,- panying drawings, wherein.:

Figure 1 is an axial, sectional View through a spray nozzle illustratingthe application of my invention thereto;

Figure 2 is a sectional view taken on line 2-2 of Figure 1; and v Figure3 is a sectional View taken on line 3--3 of Figure 1; and

Figure 4 is an enlarged view of that portion enclosed in dot-dash linesat the left in Figure 1.

Referring in detail to the drawings, Figure 1 includes an adaptor I2,which, for convenience, will also be referred to as a nozzle block andmay be formed of any metal commonly used in nozzles. The adaptor ornozzle block I2 is preferably polygonal in cross-section for conveniencein applying it in an installation. The nozzle block I2 is provided witha bore i3 formed in the rear thereof eccentric to the axis which isadapted for attaching by soldering, brazing or screwing a pipe or leadill for the flow of fuel under pressure from a convenient source (notshown), into the bore I3 and through the nozzle assembly. Ahead of thebore I3 and communicating therewithis a reduced bore I5 leading to andcommunieating with a circular space or cavity I6 which, in the iinalnozzle assembly, becomes an annular space. Ahead. of the space I6 is athreaded opening I'I of a diameter less than the space I6 and interiorlythreaded to receive the nozzle proper.

The adaptor or nozzle block I2 is provided. with an axialbore i8 for thereception by means of a press t of a pipe I9 which forms a returnconduit to the source of fuel. A reduced bore 2li leads inwardly fromthe bore i8 and communicates with the space I6 and opening El. Anannular seat 2l surrounds the inner end of the bore 2i?.

The nozzle proper includes a nozzle body 2-'i having a central portion26 which may also be polygonal in cross-section, and a rearward reducedportion 28 exteriorly threaded and adapted to be threaded into thethreaded opening Il. A shoulder 6i! is formed on the rear face of thecentral portion 2S for seating against the front face of the nozzleblock i2 around the threaded opening Il. Ahead of the central-portion E@is a tapered front portion 32. The whole nozzle body 24 has a centralbore, the main portion of which is indicated at 34 and extends to therear of the nozzle Ibody 24 where it communicates with the space I6. Therear portion of the bore 34 is threaded as indicated at 35. The forwardend of the bore 34 has a reduced portion 38 terminating` in a stillfurther reduced portion vlll). A tapered shoulder 132 is formed betweenthe reduced portion 3.8. and the rear main portion of the bore 34.

An insert or nib 44 is press fitted into the portion 38 of the bore 34,and has an extension fitted in the portion 42 of the bore, the frontface of the nib being substantially ush with the front face of the frontportion 32 of the nozzle body. The nib 44 is provided with an axialorifice 46 having a central cylindrical portion, a diverging outlet 48and a rearward diverging surface 50 from which leads another divergingsurface 52.'

The diverging surface 52 is of wide angle conical formation andterminates at a point slightly short of the shoulder 42.

A distributor indicated as a Whole at 54 is inserted in the bore 34 ofthe nozzle body 24. distributor 54 includes a head portion 55 having atruncated, conical front surface 58 in which are provided a plurality ofslots or channels 69. 'lhe slots 6i] lead from the space around the head55 in the bore 34 to points adjacent the diverging surface B in the nib44. The center of the front face 58 of the head 5 is flattened asindicated at 62 and forms with the conical surface 59 a swirl chamber64. tangentially with respect to the true radius of the head 55, as willbe evident from Figure 3. It will be noted that the slots S6 formsubstantially a continuation of the shoulder 42, leading from the bore34 to the swirl chamber 54.

Centrally of the distributor 54 is an enlargement 56 having exteriorthreads for securing the distributor in the threaded interior of thebore 34. The enlargement 55 is provided with a y plurality of openingsS8 disposed substantially parallel with the axis of the device.Rearwardly of the enlargement 56 of the distributor 54 is a reduced end'i9 forming a shoulder f2. The distributor 54 is provided with a passagei4 communicating axially with the swirl chamber 64. A passage 'I6 formedin the distributor communicates with the passage '14, extends throughthe distributor 54, and communicates with the bore 20. Sealing means 82is interposed between the shoulder 'l2 and the annular seat 2 I.

The following passages together form a by-pass channel, namely, I4, n,29, and I8, which lead directly from the swirl chamber 64 to the returnconduit I9, and the means for returning the bypassed fuel to the sourceof supply.

An interceptor plug 8E is interposed in the bypass channel by insertingit in the bore 29 between the reduced end 'I0 of the distributor 54, andthe inner end of the pipe I9. The interceptor plug 39 is in the form ofa disk having substantial thickness in axial direction and, as viewed inFigure 2, is provided with a plurality of openings 95 formed around theperiphery thereof. In the preferred forni of the interceptor plug 88,the openings 90 are three in number and disposed at the periphery of thedisk, although other positions may be desired on occasion, and adifferent number may be preferred. The total net cross The The slots Si]are disposed sectional area of the openings 99 is less than the crosssectional area of the passage I4.

The interceptor plug 88 is inserted in the bore 78 by means of a pressfit securement and the nozzle assembly is otherwise a standard articleof production whereby it will be seen that the nozzle assembly does notneed to be re-designed for the inclusion of the interceptor plug 89.

Operation Fuel under pressure is supplied by any conthe slots 60 intothe swirl chamber 64. The tangential disposition of the slots 60produces a swirling action of the fuel whereby, by centrifugal force, itfollows the periphery of the swirl chamber. The quantity or mass of fuelin the swirl chamber is indicated at 92 in Figure 4. In the swirlingmotion of a quantity. of fuel, such as here described, the Velocity ofthe liquid increases toward the center of the swirl chamber, i. e., itvaries inversely as the distance from the center of rotation. Also, atany point of the radius of the swirl chamber, the mathematical productof the velocity times the pressure is constant, or substantially so,except for friction losses. Since the velocity increases toward thecenter, the pressure must decrease and, at a certain point, the pressureat the center may reach a minus quantity. In such a condition, airenters the oriiice of the nozzle to fill the vacuum and forms a hollowvortex. Such a hollow vortex is illustrated at 94 in Figure 4.

Considerably more fuel is injected or forced through the nozzle assemblythan is intended to be used in the combustion space. The by-pass channelis utilized for withdrawing that portion of the fuel from the nozzleassembly which is not intended to be used in combustion. By retainingconstant the pressure forcing the fuel through the nozzle, and varyingthe withdrawal of 'fuel through the by-pass channel, the amount of fuelemerging from the orifice of the nozzle into the combustion space can beregulated in constant ratio to the quantity of fuel Withdrawn throughthe by-pass channel. This arrangement is in contrast with other types offuel nozzles in which the fuel emerging from the orifice is inproportion to the square root of the pressure applied.

Heretofore and before the present invention, when fuel was withdrawnthrough the by-pass channel, a portion of the fuel indicated at 92 wasdrawn through the passage 'I4 in the head 56 of the distributor 54. Whena considerable quantity of fuel was so withdrawn, the wall of fuel 92covering the passage 14 became depleted, and the air from the hollowvortex 94 passed into the by-pass channel and interfered with thedesired procedure of directly returning the bypassed fuel into thesource of supply. When such air was permitted to enter the by-pass ductI9, it caused operating difculties by being ultimately conveyed to thefuel pump, where it collected, impairing the functioning of the pump,and also by being conveyed into the fuel supply line where it interferedwithl the precise control of fuel ow rate and positive shut olf.

In the present instance, the interceptor plug 38 prevents the passage ofair from the hollow vortex 94 into the by-pass channel. The openings 90in the interceptor plug 88 are of less total cross-sectional area thanthe cross-sectional area of the passage 'I4 and, of course, less thanthe cross-sectional area of the passage l5. This restriction amounts toa temporary obstacle in the flow of fuel'through the by-pass channel andproduces a backing-up pressure through the passage 16 and into the'passage Ill and exerting itself at the point of communication betweenthe venient means through the pipe I4 from which it passes throughvarious passages, such as bore I5, space I6, bore 34, holes 68, andfinally through passage 'I4 and Ythe swirl chamber 54. This backing-uppressure prevents the emergence of air from the hollow vortex 94 intothe by-pass channel. However, the effect of this backing-up pressureupon the rate of fluid discharge from the nozzles orifice 45 isnegligible because an increase in fluid pressure L at the center of theby-pass opening 14 does not produce an equal increase in pressure at theperiphery of the discharge orice 46.

When fuel is drawn through the openings 9U in the interceptor plug 88 itis replaced by additional fuel drawn from the swirl chamber 64 throughthe passage 14. Therefore, fuel flows through the by-pass channel asfreely as desired, while sufficient pressure is retained between theinterceptor plug 88 and the swirl chamber 64 to prevent the passage ofair into the by-pass channel.

It will be seen from the foregoing that an efflcient and effectivedevice has been produced for accomplishing the purposes of the inventionand overcoming objections to previous types of nozzles, namely, toprevent the passage of air into, and admixture with, by-passed fuelbeing withdrawn from the nozzle and returned to the source of supply, orto the fuel pump inlet.

While I have herein shown and described a preferred embodiment of myinvention, manifestly it is susceptible of modication and rearrangementof the parts without departing from the spirit and scope thereof. I donot, therefore, wish to be understood as limiting my invention to theprecise form herein disclosed, except as I i may be so limited by theappended claims.

I claim as my invention:

1. In a combustion spray nozzle having a nozzle block, an inlet channelformed in said block, a nozzle body secured in said block, said bodyhaving a swirl chamber formed therein, tangential passages communicatingbetween said lnlet channel and swirl chamber, an axial nozzle outletfrom said swir1 chamber, a by-pass bore formed in said nozzle block, aby-pass channel formed in said nozzle body leading axially from saidswirl chamber and communicating with said by-pass bore, said by-passchannel being of less cross-sectional area than the cross-sectional areaof said by-pass bore, the improvement comprising an interceptor plugsecured in said by-pass bore at a point remote from said by-passchannel, said interceptor therein of less cross-sectional area than saidbypass channel.

2. In a combustion spray nozzle having a fuel supply inlet channeltherein, a swirl chamber in communication with said inlet channel,tangential passages communicating between said inlet channel and saidswirl chamber, a nozzle outlet from said swirl chamber, and an axialbypass channel leading from said swirl chamber, said by-pass channelhaving a portion of reduced cross-sectional area communicating with saidswirl chamber, the improvement comprising an interceptor plug secured insaid by-pass channel at a point remote from said reduced portion, saidinterceptor plug having an opening therethrough, said opening being ofless cross-sectional area than the cross-sectional area of said reducedportion of said by-pass channel.

3. A combustion spray nozzle comprising, in combination, a nozzleassembly having a conical swirl chamber, said swirl chamber therebyhav-- plug having an opening ing a small-diameter end and alarge-diameter end, a nozzle outlet leading axially and centrally fromthe swirl chamber through the small-diameter end thereof, an inletchannel entering tangentially into said swir1 chamber and adapted fornow of fuel therethrough into the swirl chamber in a swirling motion,said swirling motion tending to produce a hollow vortex in said swirlchamber, a single by-pass channel leading axially and centrally from theswirl chamber through the large-diameter end thereof and adapted for thewithdrawal therethrough of fuel from the swirl chamber, and aninterceptor plug in said by-pass channel at a point remote from thepoint of communication of the by-pass channel with the swirl chamber,said interceptor plug having openings therethrough of less totalcross-sectional area than the cross-sectional area of the by-passchannel at its point of communication with the swirl chamber.

4. A combustion spray nozzle comprising, in combination, a nozzleassembly having a conical swirl chamber, said swirl chamber therebyhaving a small-diameter end and a large-diameter end, a nozzle outletleading axially and centrally from the swirl chamber through thesmall-diameter end thereof, an inlet channel entering tangentially intosaid swirl chamber and adapted for flow of fuel therethrough into theswirl chamber in a swirling motion, said swirling motion tending toproduce a hollow vortex in said swirl chamber, a single by-pass channelleading axially and centrally from the swirl chamber through thelarge-diameter end thereof and adapted for the withdrawal therethroughof fuel from the swirl chamber, said by-pass channel having a portion ofreduced cross-sectional area communicating with the swirl chamber, and aportion of enlarged cross-sectional area posterior to said reducedportion with respect to the flow of fuel therethrough, and aninterceptor plug in said enlarged portion at a point remote from saidreduced portion, said interceptor plug having openings therethrough ofless total crosssectional area than the cross-sectional area of saidreduced portion of the by-pass channel.

EUGENE O. OLSON.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 625,466 Randolph May 23, 1899748,971 Millspaugh Jan. 5, 1904 1,326,488 Fisher Dec. 30, 1919 1,620,209Ihne Mar. 8,'1927 2,037,645 Vroom et al Apr. 14, 1936 2,079,430Bargeboer May 4, 1937 2,315,172 Voorheis Mar. 30, 1943 2,323,001Bargeboer June 29, 1943 2,345,402 Lubbock et al Mar. 28, 1944 2,373,707vPeabody Apr. 17,` 1945 2,374,041 Saha Apr. 17, 1945

